Fan wheel driven in only one rotational direction

ABSTRACT

A fan wheel including a fan wheel hub with fan blades supported rotatably on the fan wheel hub so as to extend radially therefrom, and a fan wheel drive accommodated in the fan wheel hub so as to be rotatable relative thereto within a limited angular range and connected to the fan blades for a corresponding rotation of the fan blades about their longitudinal axes, whereby the flow direction of the fan wheel is reversible by an inertia-based rotation of the fan wheel relative to the fan wheel drive.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of pending internationalpatent application PCT/DE2019/100480 filed May 31, 2019 and claiming thepriority of German Patent Application No. 10 2018 114 534.9 filed Jun.18, 2018. The aforesaid pending international applicationPCT/DE2019/100480 and German Patent Application No. 10 2018 114 534.9are both incorporated herein by reference as though fully set forth.Reference is also made to co-pending U.S. patent application Ser. No.17/025,284 filed Sep. 18, 2020, by the present applicant, IE ASSETS GMBH& CO. KG, for an invention, entitled “Fan Wheel Driven In Only OneRotational Direction”.

BACKGROUND OF THE INVENTION

The invention concerns a fan wheel which is driven in only onerotational direction with fan blades which extend radially from the fanwheel hub in which they are supported so as to be rotatable about theirblade axes and are driven by the hub. The fan blades are inclined withrespect to the plane of rotation of the fan wheel and their inclinationis switchable via a switch-over plane extending transverse to the planeof rotation of the fan wheel so that their blade angles can be adjustedto opposite blowing directions.

Such fan wheels are generally known but are provided with expensivemeans for the adjustment of the inclination of the blade angle withrespect to the plane of rotation of the fan wheel, in particular withrespect to a switch-over of the fan blades to an opposite blowingdirection through a switch-over plane extending transverse to the planeof rotation of the fan wheel.

It is the object of the present invention to provide means forsimplifying this procedure with regard to the functional conditions aswell as with regard to the implementation of the switch-over procedure.

SUMMARY OF THE INVENTION

A fan wheel including a fan wheel hub with fan blades supportedrotatably on the fan wheel hub so as to extend radially therefrom, and afan wheel drive accommodated in the fan wheel hub so as to be rotatablerelative thereto within a limited angular range and connected to the fanblades for a corresponding rotation of the fan blades about theirlongitudinal axes, whereby the flow direction of the fan wheel isreversible by an inertia-based rotation of the fan wheel relative to thefan wheel drive.

In this way, caused by a speed reduction of the fan wheel drive up to aninterruption of the drive, with a stop-limited free movability of thefan wheel for driving the fan blades to a switch-over plane byinertia-based mass-force dependent rotation of fan wheel and by anaerodynamic impact the fan blades can be rotated about the fan bladeaxes for a switch-over to the opposite blow directions of the fan wheel.The rotational or turning movements of the fan blades in the switch-overplane can in this way be initiated, supported and/or accelerated so thatthe switch-over of the fan blades between opposite flow directionpositions of the fan blades can be achieved with very short switch-overtimes.

With the use of available operating capabilities the solution accordingto the invention can be realized without additional expenditures. Thiscan be done in particular with common measures since controls for thedrive of the fan wheels are generally anyway present and the utilizationof mass forces depending on speed changes of the drive are possiblewithout additional expenditures. The stop-limited free-wheeling movementof the fan wheel permits further an inertia-based rotation of the fanwheel: By a rapid speed reduction or interruption of the drive force or,respectively, a rapid acceleration of the drive offers the angularpositions of the drive relative to the fan wheel can be changed forinfluencing the adjustment of the angular position of the fan bladesabout the blade axes for opposite blowing directions or for a correctionbased on aerodynamic points of view.

The possible effects on the operation of the fan wheel and onoperation-dependent corrections in the mode of operation such as forexample the switch-over from a suction operating mode of the fan wheelto a blowing operating mode as provided by the present invention areachieved via effects which are dependent on the adjustment of the angleof the wheel blades for opposite blowing directions while the fan wheeldirection of rotation remains the same. Starting for example from asuction mode of operation, with the same direction of rotation of thefan wheel, the fan blades can be rotated about the blade axes in aneutral switch-over plane which extends normal to the plane of rotationof the fan wheel to a blowing operating mode by a decrease of the fandrive speed. With an increasing speed of the drive, the blades can berotated about their blade axes in an opposite direction to be pivotedagain to the original suction generating operating position.

In accordance with this operating sequence and the stop-limited idlemovement of the fan wheel with regard to the drive, the fan wheeloperation can be controlled between a suction and blow operation solelydepending on a change of the drive speed. And this can be achievedalmost without additional control expenditures. If necessary, this canbe made dependent on desirable additional functions, such as aswitch-over between suction and blowing operation based on a pressureapplication dependency or pressure application basis.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, the fan wheel is described in particular with regard to thefunctional conditions with respect to a simplified basic design. Furtherdetails are explained with reference to the accompanying drawings, whichshow in:

FIG. 1 a front view of the fan wheel including a central, driven hubwith radially extending fan blades which are inclined with regard to theplane of rotation of the blade wheel corresponding to the desired flowdirection at a certain blade angle and whose rotational positions aroundthe blade axes are stop-limited in their opposite blowing direction endpositions,

FIG. 2 a schematic representation of the fan wheel in a front view of afan blade which is inclined with regard to a plane of rotation of thefan wheel by a blade angle,

FIG. 3 a schematic and simplified cross-sectional view of the fan wheeltaken along line III-III in FIG. 1, and

FIG. 4 an operating sequence representation of a fan wheel driven inonly one direction for the adjustment of the radial blades which aresupported in the wheel hub so as to be rotatable about their radiallyextending axes for obtaining opposite flow directions. For switching theflow direction from one to the opposite direction via a switch-overplane which extends normal to the plane of rotation of the fan wheel,the fan blades are rotated about their radial axes. To this end, thespeed of the drive of the fan wheel is reduced or, respectively,increased whereby the fan blade is rotated by the resultinginertia-based rotation of the fan wheel with respect to the fan drive toa position in which the flow direction provided by the fan wheel ischanged.

DETAILED DESCRIPTION OF A PARTICULAR EMBODIMENT OF THE INVENTION

FIGS. 1 and 3 show a fan wheel according to the invention with respectto its essential components. It is designated as a whole with thereference numeral 1. The fan wheel 1 comprises a hub 2 on thecircumference thereof radially extending fan blades 3 are arranged. Asshown in FIG. 3, the fan blades 3 have, at their feet, blade journals 4via which they are supported in the hub 2 so as to be rotatable abouttheir radial blade axes 5. In this way, they are each adjustable togenerate flows in opposite directions by a rotation over a switch-overplane 9 forming a neutral plane n which extends normal to the plane ofrotation 6 of the fan wheel 1. The direction of rotation of the fanwheel 1 is indicated in FIG. 2 by the reference numeral 19. The, inaccordance with the blade angle 7 forward-facing, front side of the fanblade 5 is designated by the numeral 21.

The interior 8 of the hub accommodates the drive 10 of the blade wheel1, preferably an electric motor, arranged so as to support the hub 2.The drive 10 is rotatable about its axis 17 relative to the hub 2 withinlimits formed by stops. The hub 2 includes a cover part 13 whichcorresponds to a base part 14 surrounding the drive 10 radially in thearea of the blade journals 4. The cover part 13 is provided with thestops in the form of pin-like elements 11 arranged opposite the drive 10that is facing the drive 10 and extending into guide slots 12 formed inthe drive 10 and limiting the range of rotation of the drive 10 relativeto the hub 2 in which the drive 10 is accommodated. The drive 10 isprovided, preferably at its front side facing the cover part 13, with anannular gear ring 15 which is in engagement with pinions 16 provided onthe foot end journals 4 so as to form a drive connection of the drive 10with the fan blades 3. The use of cam- and/or eccentric drives is alsopossible in connection with the invention, not shown in the drawings.

With the stop-limited rotatability of the hub 2 with respect to thedrive 10, the fan blades 3 can be transposed via the switch-over plane 9so as to blow in opposite flow directions while the direction ofrotation 19 of the fan wheel 1 remains the same. As shown in FIG. 4 thefan wheel 1 can therefore be operated in a suction or a blowing mode,that is, for example in a suction cooling mode or in a blowing cleaningmode of operation simply by pivoting the fan blades 3 through theswitch-over plane 9 to the respective opposite blowing direction.Hereby, the fan blades 3 are in each case so oriented that the samefront blade side 21 faces the incoming air so that the same operatingconditions are provided for the suction and the blowing operation.

In accordance with the present invention the switch-over of the fanblades 3 is initiated by a rapid reduction of the speed of the drive 10.With this speed reduction and a correspondingly reduced aerodynamic airimpact on the fan blades 3, the inertia force of the fan wheel causesthe switch-over via the switch-over plane 9 of the blades 3. Theswitch-over plane 9 is shown in the operating sequence representation ofFIG. 4 as an area delimited by dashed lines in which a rapid speedreduction of the drive 10 occurs by the interruption of the drive 10resulting in the inertia-based rotation of the fan wheel correspondingto the adjustment range of the fan blades 3.

In accordance with the switch-over of the fan blades 3 in the area ofthe switch-over plane 9 from a suction operation assumed to be a normaloperation—indicated in FIG. 4 by the numeral 22—to a blowoperation—indicated in FIG. 4 by the reference numeral 23—has beenestablished after passage through the switch-over plane 9. If such aswitch-over is performed for example for cleaning purposes this may bein particular a short-period operation. In other applications it may befor longer operations. In any case, the fan wheel can again be returnedto the normal operation 22 assumed to be the suction operation as shownin FIG. 4 again dependent on the drive speed. To this end, however, theprevious procedure is reversed in that the speed is increased, inparticular rapidly increased, which results in a switch-over of the fanblades 3 via the switch-over plane 9 to a suction operation.

Such reversibility of the fan wheel 1 with respect to the flow directioncan also be combined with a possibility to adjust the blade angle 7 ofthe fan blade 3 with respect to the amount of air moved by the fan wheelwhich would provide for further application possibilities.

Concerning the different application possibilities for the fan wheel itmay be expedient to vary the stop-limited rotation range of the fanwheel hub 2 with respect to the drive 10. The drive 10 can be rotatablerelative to the fan wheel hub 2 within elastic stop limits, for example,dependent on thermal set values using thermo elements, shape memorymaterials or similar. In this respect, it may also be expedient tochange the rotational position of the annular gear ring 15 in the drivetrain of the drive 10 and/or to the hub 2.

As a result, with the present invention a fan wheel 1 is provided whichis rotatable only in one direction but whose fan blades 3 are rotatableabout the radial fan blade axes 5 in a switch-over plane 9 which extendsnormal to the plane of rotation 6 of the fan blades 3 by aninertia-based rotation of the fan wheel 1 with respect to the fan drive10 and by an aerodynamic impact on the fan blades 3 to move the air inan opposite directions.

LISTING OF REFERENCE NUMERALS

-   1 fan wheel-   2 hub-   3 fan blade-   4 blade journal-   5 radial blade axis-   6 plane of rotation-   7 blade angle-   8 interior of hub-   9 switch-over plane-   10 drive-   11 pin-like stop elements-   12 guide slot-   13 cover part-   14 base part-   15 annular gear ring-   16 pinion-   17 drive axis-   19 direction of rotation-   21 forward facing front side-   22 suction operation-   23 blow operation-   n neutral plane

What is claimed is:
 1. In a fan wheel (1) driven in only one directionof rotation, comprising a fan wheel hub (2) rotatable relative to a fanwheel drive (10) in a stop-limited manner and having fan blades (3)extending radially from the hub (2) of the fan wheel (1) and beingsupported by the fan wheel hub (2) so as to be rotatable about the bladeaxes (5) with a blade angle (7) which is inclined relative to a plane ofrotation (6) of the fan wheel (1) and which is adjustable via aswitch-over plane (9) which extends transverse to the plane of rotation(6) of the fan wheel (1) to provide for an opposite direction of theflow generated by the fan wheel (1), wherein the blade angle (7)relative to the switch-over plane (9) is adjustable by a reduction ofthe drive speed of the fan wheel (1) resulting in an inertia-basedrotation of the fan wheel (1), the fan blades (3) are switched toopposite flow directions by an aerodynamic force application, and in thearea of the switch-over plane (9), the fan blades (3) can be switchedbetween the opposite direction flow generating positions by a rapidspeed reduction of the drive (10) of the fan wheel (1) resulting in anover-running inertia based rotation of the fan wheel (1) and,respectively, by a rapid increase of the speed of the drive (10) withrespect to the speed of the fan wheel (1).
 2. A fan wheel (1) driven inonly one direction of rotation according to claim 1, characterized inthat the drive (10) is rotatable relative to the fan wheel hub (2)within elastic stop limits.
 3. A fan wheel (1) driven in only onedirection of rotation according to claim 1, characterized in that thedrive (10) is rotatable relative to the fan wheel hub (2) within stoplimits by at least one thermo element.
 4. The fan wheel (1) driven inonly one direction of rotation according to claim 1, characterized inthat the fan wheel hub (2) includes a cover part (13) including pin-likestop elements (11) extending cover part (13) operatively arranged facingthe drive (10), the drive (10) having guide slots (12) arranged forreceiving the pin-like stop elements (11), wherein a range of rotationof the hub (2) about a drive axis (17) of the drive (10) is limited bythe pin-like stop elements (11) within the guide slots (12).